@anonforthis88 I couldn't read this and not comment. You are far from a shit parent, you have sought an appropriate outlet where you can vent and ask for advice.
It sounds like you're having a pretty shit time of it at the minute, just gonna say it how it is! My DD is 22months and I'm right there with you, we're having an awful time with sleep at the minute (although it has coincided with her pre-molars coming in so at least I can guess a lot of is pain related).
Please don't worry about 'bad habits' being formed if they make your life easier now, if they don't make your life easier now, try something else that might (even if that might be sleep training).
Personally, I don't believe in sleep training but I can tell you something, I would never judge anyone that did it. Everyone has a different tolerance of sleep deprivation and what their mental health can manage and if something works for you and makes you a happier, healthier person, bloody go for it.
As for instagram and facebook, try to remember anything you see is a snapsnot of a good time, minutes, even seconds before that photo is taken it could have been a completely different story. Not sure if you follow biglittlefeelings already but I find them so honest with what daily life with a toddler looks like, and they share 'meltdown mondays' which really reassures you that others are also having a shit time of it.
I know it's hard (I could've cried last night at 4am when my DD woke for the 4th time - and wouldn't settle for 40 minutes each time) but try to focus on the positives. It sounds like you have an incredibly supportive DH who isn't afraid to be right in the thick of it with you. You are both your DS's world and it's nice that he seeks comfort in the both of you when he's having a tough time.
I think you would benefit from some time with just you and your partner, I'd enlist someone you trust and be honest. My in-laws looked after our DD a few months ago while we went for a meal and I told them she might not sleep easily and they just looked me dead in the eye and said 'One night of difference won't kill her, if she's upset we'll bring her downstairs and she can watch tv with us'. She didn't go to sleep easily for them, they did bring her downstairs, she did watch tv, she then fell asleep and they put her in her cot. We got home around 11pm, I expected for her to wake a lot... but no, she slept through. So they were right, one night didn't kill her, but it did re-energise us.
Wishing you all the best for a restful evening and good nights sleep. My inbox is always open if you want to lament to someone going through something similar.